Obstructive sleep apnea

Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common sleep disorder. It occurs when tissues in the upper airways come too close to each other during sleep, temporarily blocking the inflow of air.

Who is at Risk

OSA can develop in anyone at any age but most often occurs in people who are:

• Overweight
• Male
• Age 40 and older

Guidelines for Obstructive Sleep Apnea in Adults

Guidelines on diagnosis and treatment of adult OSA from the American College of Physicians recommend:

• Sleep tests should be reserved for patients who experience daytime sleepiness (the main symptom of OSA).
• Overnight sleep tests in a sleep center lab (polysomnography) are the best way to diagnose OSA. Home sleep tests using portable monitors are an option for patients who do not have access to sleep centers, but they are not appropriate for patients who have serious health conditions.
• Losing weight is an important first step for patients with OSA who are overweight or obese.
• Continuous positive airway pressure (CPAP) is the most effective treatment for moderate-to-severe OSA. Although these devices can take some time to get used to, most patients find that CPAP greatly improves their symptoms and quality of life.
• Mandibular advancement devices (MADs), a type of dental device, may be an alternative therapy for patients with mild sleep apnea and who cannot tolerate or use CPAP treatment.

Recommendations for Obstructive Sleep Apnea in Children

Basic recommendations for children include:

• Surgical removal of enlarged adenoids and tonsils (adenotonsillectomy) is the first-line treatment for childhood OSA.
• CPAP treatment is recommended if the sleep apnea persists.
• Intranasal corticosteroids are an option for children with mild obstructive sleep apnea.
• Weight loss is recommended in addition to other therapies for children who are overweight or obese.

Obstructive sleep apnea (OSA) is a disorder in which a person temporarily stops breathing during the night, perhaps hundreds of times. These gaps in breathing are called apneas. The word apnea means "absence of breath." An obstructive apnea episode is defined as the absence of airflow for at least 10 seconds.

Sleep apnea is often accompanied by snoring, disturbed sleep, and daytime sleepiness. Many people with OSA do not even know they have the condition.

Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) occurs when tissues in the upper throat relax and come together during sleep, temporarily blocking the passage of air. In general, OSA occurs as follows:

• On its way to the lungs, air passes through the nose, mouth, and throat (the upper airway).
• Under normal conditions, the back of the throat is soft and tends to collapse inward as a person breathes. Dilator (widening) muscles work against this collapse to keep the airway open.
• If the tissues at the back of the throat collapse and momentarily block the airway, apnea occurs. Apnea is when breathing is temporarily stopped. In most cases, people are unaware of it, although sometimes they awaken and gasp for breath. Bed partners are often the first to notice the problem.
• In some cases, the interference is incomplete and causes continuous but slow and shallow breathing (hypopnea). In response, the throat vibrates and makes the sound of snoring. Snoring can occur whether a person breathes through the mouth or the nose. (Snoring often also occurs without apnea.)
• Apnea decreases the amount of oxygen in the blood. This lack of oxygen triggers the brain to send extra activating signals to the breathing muscles to restart breathing.
• At this point, the sleeping person may make a gasping or snorting sound but does not usually fully wake up. Nevertheless, these "wake up" episodes lead to poor sleep quality and many other problems described below.

Obstructive sleep apnea in adults is defined as 5 or more episodes of apnea or hypopnea per hour of sleep (called apnea-hypopnea index or AHI) in individuals who have excessive daytime sleepiness. People with 5 to 15 episodes of apnea or hypopnea per hour of sleep are considered to have mild sleep apnea, 15 to 30 episodes/hour is moderate sleep apnea, and more than 30 episodes per hour indicates severe disease.

A diagnosis of OSA in children can be made when both symptoms of OSA and an abnormal sleep study are present. Any number of apneas and hypopneas in children is abnormal.

Clinical symptoms of OSA in children may include:

• Snoring
• Labored breathing, gasping, choking, pauses in breathing that are present during sleep
• Sleepiness, hyperactivity, behavioral problems, or learning problems

Abnormal sleep study (PSG) findings may include:

• One or more obstructive apneas, mixed apneas, or hypopneas, per hour of sleep
• A pattern of obstructive hypoventilation

Other Types of Apnea

• Central sleep apnea is much less common. It is caused by a problem in the central nervous system, most often a failure of the brain to signal the airway muscles to breathe. In such cases, oxygen levels drop abruptly and usually the sleeper wakes up. Often people with central sleep apnea recall waking up. Heart failure is a common cause of central sleep apnea.
• Mixed apnea is the term used when central and obstructive sleep apneas occur together. Sometimes patients with severe OSA have mixed apnea.
• Upper airway resistance syndrome (UARS) is a condition in which patients snore, wake frequently during the night, and have excessive daytime sleepiness. However, patients do not have the breathing abnormalities that characterize sleep apnea and they do not show a reduction in blood oxygen levels. Treatments are similar to those for sleep apnea.

All of the muscles in the body relax during sleep. In people without obstructive sleep apnea, the throat muscles relax but do not block the airways. In patients with obstructive sleep apnea, the airways become temporarily blocked or narrowed during sleep, preventing air from flowing normally into the lungs.

Certain physical characteristics of the face, skull, and neck can affect the size of the airway.

Large Neck

A large neck (17 inches [43 centimeters] or greater in men and 16 inches [40 centimeters] or greater in women) is a risk factor for sleep apnea. While some people's necks are naturally larger than others, being overweight or obese can contribute to having a large neck.

Facial and Skull Characteristics

Structural abnormalities in the face and skull contribute to many cases of sleep apnea. These abnormalities include:

• Undersized lower jaw or chin (micrognathia)
• Receding lower jaw (retrognathia)
• Narrow upper jaw
• Enlarged tongue
• Enlarged tonsils

Soft Palate Characteristics

Some people have specific abnormalities in the soft area (palate) at the back of the mouth and throat that may lead to sleep apnea. These abnormalities include:

• The soft palate is stiffer, larger than normal, or both. An enlarged soft palate may be a significant risk factor for sleep apnea.
• The soft palate and the walls of the throat around it collapse easily.

Muscle Weakness

Abnormalities or weakness in the muscles that surround the airway can also contribute to obstructive sleep apnea.

Causes of Obstructive Sleep Apnea in Children

Sleep apnea occurs in about 2% of children and can occur even in very young children. The most likely causes include:

• Facial or skull abnormalities in infants such as brachycephaly, a birth defect in which the head tends to be shorter or wider than average. Facial abnormalities may be associated with congenital or genetic disorders such as Down syndrome.
• Overgrown tonsils, adenoids, or both in small children. Removal of the enlarged adenoids and tonsils (adenotonsillectomy) can free the airways and may correct the problem.
• Neuromuscular disorders such as cerebral palsy that affect the muscles in the airways.

More than 18 million Americans have sleep apnea. The incidence of obstructive sleep apnea (OSA) has been increasing, due in part to rising rates of obesity.

Sex

Obstructive sleep apnea is more common in men than in women. Men tend to have larger necks and weigh more than women. However, women tend to gain weight and develop larger necks after menopause, which increases their risk of developing sleep apnea.

Female reproductive hormones appear to play a protective role in sleep apnea. Declining estrogen levels are another reason that postmenopausal women face more risk for sleep apnea than premenopausal women.

Age

Sleep apnea is most common in adults ages 40 to 60 years old. Middle age is also when symptoms are worse. Nevertheless, sleep apnea can affect people of all ages, including children.

Race and Ethnicity

African Americans face a higher risk for sleep apnea than any other ethnic group in the United States. Other groups at increased risk include Pacific Islanders and Hispanics.

Family History

People with a family history of OSA are at increased risk of developing the condition.

Excess Weight

Being overweight is a major risk factor for OSA, especially when the fat distribution results in increased neck circumference. Excess weight may also contribute to sleep apnea when fat deposits increase tongue size or fill throat tissue. Even a moderate amount of weight gain can raise a child's or adult's chances of developing sleep apnea.

Smoking and Alcohol Use

Smoking

Smokers are at higher risk for apnea. Those who smoke more than two packs a day have a risk 40 times greater than nonsmokers.

Alcohol

Alcohol use may be associated with apnea. Patients diagnosed with sleep apnea are recommended not to drink alcohol before bedtime.

Medical Condition Risk Factors

Diabetes

Type 2 diabetes is associated with sleep apnea. It is not clear if there is an independent relationship between the two conditions or whether obesity is the common factor.

Gastroesophageal Reflux Disease (GERD)

GERD is a condition caused by acid backing up into the esophagus. It is a common cause of heartburn. GERD and sleep apnea often coincide. Research suggests that the backup of stomach acid in GERD may produce spasms in the vocal cords (larynx), thereby blocking the flow of air to the lungs and causing apnea. Apnea itself may also cause pressure changes that trigger GERD. Obesity is common in both conditions, and more research is needed to clarify the association.

Hormonal Disorders

Hypothyroidism (underactive thyroid gland) and acromegaly (overactive pituitary gland) are endocrine disorders that increase the risk for obstructive sleep apnea. Polycystic ovary syndrome (PCOS), a disorder caused by imbalances in female hormones, is also highly associated with sleep apnea. Women with PCOS are also more likely to have diabetes and obesity, which are additional risk factors for sleep apnea.

Medications

Prednisone and other corticosteroids can also lead to more fat accumulation in the neck area, increasing the likelihood of sleep apnea. Sedative medications like benzodiazepines can also lead to more OSA.

Obstructive sleep apnea can lead to a number of complications, ranging from daytime sleepiness to possible increased risk of death. Sleep apnea has a strong association with several diseases, particularly those related to the heart and circulation.

Excessive Daytime Sleepiness, Accidents, and Quality of Life

Excessive daytime sleepiness is the most noticeable, and one of the most serious, complications of sleep apnea. It interferes with mental alertness, social relations, and quality of life. People with obstructive sleep apnea are more likely to suffer from depression and may be at risk for sexual dysfunction.

Daytime sleepiness can also increase the risk for accidents and related injuries. Many studies have shown that people with sleep apnea have a significantly increased risk for drowsy driving and car accidents. Untreated sleep apnea is a major risk factor for injury at factory and construction work sites.

Heart and Circulation Complications

Sleep-disordered breathing is very common among patients with heart problems such as high blood pressure, heart failure, pulmonary hypertension, stroke, heart attack, and atrial fibrillation. This link may be because both cardiovascular conditions and sleep apnea share a common risk factor of obesity. However, increasing evidence suggests that severe OSA is an independent risk factor that may cause or worsen a number of heart-related conditions.

High Blood Pressure

Moderate-to-severe sleep apnea definitely increases the risk for high blood pressure (hypertension) even when obesity is not a factor. Studies suggest that CPAP may help reduce blood pressure, especially when combined with weight loss in overweight patients.

Coronary Artery Disease and Heart Attack

Sleep apnea appears to be associated with heart disease regardless of the presence of high blood pressure or other heart risk factors. Studies suggest that patients with moderate-to-severe obstructive sleep apnea have a higher risk for heart attack.

Stroke

Sleep apnea may increase the risk of death in patients who have previously had a stroke.

Heart Failure

Up to a third of patients with heart failure also have sleep apnea. Central sleep apnea often results from heart failure. Obstructive sleep apnea can cause heart damage that worsens heart failure and increases the risk for death.

Atrial Fibrillation

Sleep apnea may be a cause of atrial fibrillation (irregular heartbeat).

Other Adverse Effects on Health

Untreated obstructive sleep apnea is associated with higher incidence or complication of many medical conditions including:

• Insulin Resistance. Obstructive sleep apnea can lead to insulin resistance, a condition that increases the risk for type 2 diabetes and prediabetes. Insulin resistance is closely related to metabolic syndrome, a major risk factor for heart disease. Metabolic syndrome is marked by large waist circumference, obesity, abnormal cholesterol levels, high triglyceride levels, high blood pressure, and high blood sugar (glucose) levels.
• Asthma. Sleep apnea may worsen asthma symptoms and interfere with the effectiveness of asthma medications. Treating the apnea may help asthma control.
• Seizures. There may be an association between seizures and obstructive sleep apnea, especially in older adults. Some studies have shown treatment of obstructive sleep apnea may help in the control of refractory seizures.
• Headaches. Sleep disorders, including apnea, may be the underlying causes of some chronic headaches. In some patients with both chronic headaches and apnea, treating the sleep disorder may cure the headache.
• High-risk pregnancies. Sleep apnea may possibly increase the risk of pregnancy complications, including gestational diabetes and high blood pressure.

Effects on Bed Partners

Because sleep apnea often includes noisy snoring, the condition can adversely affect the sleep quality of the bed partner. Spouses or partners may also suffer from sleeplessness and fatigue. In some cases, the snoring can disrupt relationships. Diagnosis and treatment of sleep apnea in the patient can help eliminate these problems.

Effects on Infants and Children

Failure to Thrive

Small children with undiagnosed sleep apnea may "fail to thrive," that is, they do not gain weight or grow at a normal rate and they have low levels of growth hormone. In severe cases, this may affect the heart and central nervous system.

Behavior and Learning Problems

Poor sleep and sleep-related breathing disturbances can cause behavioral and cognitive issues. Problems in attention and hyperactivity are common in children with sleep apnea. There is some evidence that such children may be misdiagnosed with attention-deficit hyperactivity disorder. Even children who snore and do not have sleep apnea may be at higher risk for poor concentration.

People with sleep apnea usually do not remember their snoring, restless sleep, or sudden brief waking during the night.

Symptoms in Adults

Symptoms may include:

• Excessive daytime sleepiness. Excessive daytime sleepiness and fatigue are the hallmark symptoms of obstructive sleep apnea. Patients risk falling asleep during the day while performing routine activities such as reading, watching TV, sitting inactively, lying down, or riding in or even driving a car. Usually, these brief episodes of sleep do not relieve their overall sense of sleepiness.
• Restless or unrefreshing sleep. Patients often wake up feeling unrefreshed despite having a full night's sleep. Some patients experience morning headaches, dry mouth, or sore throat after awakening.
• Impaired mental or emotional functioning. Patients may have trouble with concentration, attention, or memory. They may feel irritable or depressed. Some patients experience a reduced sex drive.
• Snoring. Bed partners may report very loud and interrupted snoring, especially when patient is lying on back. Patients have frequent pauses in breathing (apneas) that last 10 to 30 seconds followed by gasping or choking that suddenly and briefly awakens them. The snoring often occurs in a crescendo pattern with the loudest noises occurring right before the gasping sounds.

Symptoms in Children

Children with obstructive sleep apnea (OSA) share certain symptoms with adults such as snoring and restless sleep, but they tend not to exhibit daytime sleepiness. Children often have symptoms that differ from adults, including:

• More effort in breathing (flaring nostrils, heaving chests, sweating). The chest may have an inward motion during sleep (paradoxical breathing).
• Behavioral difficulties without any obvious cause, such as hyperactivity and aggressiveness.
• Nighttime sweating or strange sleep positions.
• Daytime mouth breathing, stuffy nose, nasal speech.
• Failure to grow and gain weight.

In diagnosing OSA, the doctor will ask about your medical and sleep history, and conduct a physical exam. If symptoms suggest OSA or another sleep disorder, further diagnostic testing may be performed. Your doctor may recommend you have a sleep study (polysomnography) performed at a sleep disorders center or do a sleep study at home wearing a portable monitor.

The devices used for sleep studies can measure the number of respiratory events per hour. Events measured include apnea (stopped breathing), hypopnea (shallow or slow breathing), and respiratory disturbances (stopped or slowed breathing and near-awakenings caused by the effort to breathe). Based on these measurements, a sleep specialist doctor will evaluate the apnea-hypopnea index (AHI) or the respiratory disturbance index (RDI), to determine if you have OSA and, if so, whether it is mild, moderate, or severe.

OSA in adults is diagnosed when a patient has at least 15 events per hour with or without other symptoms of obstructive sleep apnea, or 5 events per hour with symptoms.

Symptoms or signs that may indicate sleep apnea include:

• Excessive daytime sleepiness is the main symptom of OSA. According to the American College of Physicians, patients who do not have daytime sleepiness DO NOT need to have a sleep study.
• Loud snoring (however, not everyone who snores has sleep apnea).
• Periods of breath holding during sleep, followed by gasps or snorts.
• Restless sleep, fatigue, insomnia.

Medical and Sleep History

To help determine the presence of OSA, the doctor may ask the following questions:

• Do you ever feel tired, feel sleepy, or lack energy during the day?
• If so, how often during the day? When does this usually occur?
• How restful is sleep?
• Do you frequently have morning headaches?
• Are you taking any medications that may affect sleep?
• Are you taking or withdrawing from stimulants, such as coffee or tobacco?
• How much alcohol do you drink each day?
• Do you have any problems with mental or emotional functioning?
• What is your normal sleeping position (back, side, or stomach)?
• If you have a bed partner, does he or she complain about your snoring, thrashing, or gasping for breath?
• Do you fall asleep almost as soon as your head hits the pillow? (May be a sign of sleep deprivation.)

Physical Examination

The doctor will check for physical indications of sleep apnea, including:

• Abnormalities in the soft palate or upper airways, including enlarged tonsils
• High body mass index (BMI) and distribution of fat (body habitus)
• A wide neck measurement (over 17 inches [43 centimeters] in men or 16 inches [40 centimeters] in women)

Ruling out Other Disorders

The doctor will also consider conditions other than sleep apnea that may cause daytime sleepiness including:

• Other sleep disorders (narcolepsy, insomnia, or restless legs syndrome)
• Medical conditions (chronic pain, hypothyroidism, gastroesophageal reflux disease, respiratory disorders)
• Medications (tranquilizers, sleeping pills, antihistamines beta blockers, and many others)
• Occupational and lifestyle factors (night or varying shift work, alcohol abuse)

Polysomnography and Sleep Lab Tests

Polysomnography (PSG) is the technical term for an overnight sleep study that involves recording brain waves and other sleep-related activity. Polysomnography is typically performed at a sleep center. The patient sleeps in a room that resembles a hotel room but is equipped with a video camera and monitoring station. Polysomnography conducted in a sleep lab is the gold standard for diagnosing sleep apnea.

The patient arrives about 2 hours before bedtime without having made any changes in daily habits. A trained technician places electrodes (similar to the sticky pads used for electrocardiograms) on the patient's face and head, a sensor on the finger, and a sensor in the nose. Special belts are placed around the waist to monitor breathing activity. These devices are all painless. They are used to collect data on eye movements, brain activity, heart rate, and oxygen levels.

Wires attached to these devices transmit data to the technician in the monitoring room. The technician will score the sleep pattern data throughout the night as the patient passes through the various sleep stages. The patient is discharged in the morning. A sleep specialist doctor will later evaluate the data that was collected and send a report to your doctor.

If you show signs of moderate-to-severe sleep apnea during your sleep, the technician may wake you up during the night to perform split-night polysomnography. In split-night polysomnography, during the second part of the night patients are fitted with a CPAP mask and receive a CPAP titration study to adjust the amount of air flow coming through the mask. In centers that do not perform split-night polysomnography, patients may need to return for a second overnight sleep study to have CPAP titration performed.

Portable Monitors and Home Sleep Tests

Diagnostic testing at home with portable monitors may be an option for patients who have a high likelihood of moderate-to-severe obstructive sleep apnea, do not have access to a sleep laboratory, and do not have any other major medical disorders. Portable monitors are not appropriate for people who have serious conditions such as chronic lung disease, heart failure, or neurological disorders (such as seizures). Patients with these conditions are at higher risk for central sleep apnea. Many portable monitors cannot distinguish between central and obstructive sleep apnea. Portable monitors are also not recommended for patients who may have other sleep disorders, such as narcolepsy.

There are different types of portable home monitors. They are classified as type II, type III, or type IV. (Sleep lab-based polysomnography is classified as type 1.) Type II monitors are the most similar to an overnight PSG study conducted in a sleep center. The main difference is that there's no technician present. Type III monitors record fewer variables than type II or type I studies, but usually evaluate several respiratory channels, heart rate, and oxygen saturation. However, they cannot distinguish between sleep and wake states. Type IV monitors are the least sophisticated devices. Type III and type IV portable monitors do not measure the apnea-hypopnea index, but can provide estimates.

Portable monitors usually come with an air-flow sensor that goes under the nose, an oxygen clip that's attached to a finger, and a belt monitor that goes around the chest. The data is collected through wireless transmission. Depending on the device, the patient may pick up the monitor at a local hospital and receive instructions from a technician, or the monitor may be shipped in the mail to the patient's home.

Weight Loss

All patients with OSA who are overweight or obese should attempt to lose weight. Weight loss reduces snoring and apnea/hypopnea episodes in many people, and may even in some cases cure OSA. Weight loss may also help improve sleep and reduce daytime sleepiness. Weight loss associated with bariatric surgery has also been shown to decrease apnea/hypopnea episodes; however, the evidence is yet limited.

Smoking, Alcohol, and Drugs

• Smokers should quit, since smoking worsens apnea
• Avoid alcohol within 4 hours of sleep
• Avoid sedatives and sleeping medications

Positional Therapy

Body position has some effect on obstructive sleep apnea, with at least twice as many apneas occurring in people who lie on their back as in those who sleep on their side. This may be due to the effects of gravity, which cause the throat to narrow when a person lies on the back. Sleeping on the back also increases the chances of snoring.

Positional therapy can help relieve snoring. However, simply trying to treat snoring will not treat sleep apnea. (Remember that snoring does not necessarily indicate sleep apnea.) Changing body position may help with mild apnea but it has little effect on severe sleep apnea.

As a first step, simply try sleeping on your side. Other suggestions for maintaining a low-risk sleeping position include:

• Sew a small pocket to the back of the pajamas and place a tennis ball or other small ball into it.
• A special pillow that helps to stretch the neck may reduce snoring and improve sleep for people with mild sleep apnea.
• Sleeping in an upright position may improve oxygen levels in overweight people with sleep apnea. Elevating the head of the bed may help.

It is important for patients to treat obstructive sleep apnea (OSA) as they would any chronic disease. OSA needs to be taken seriously given its long-term complications and its association with high blood pressure, heart problems, stroke, and diabetes. Ideally, OSA should be treated by a doctor who specializes in sleep disorders.

Recommended Treatments

The American College of Physicians recommends the following treatments for OSA in adults:

• Weight loss is the most important first lifestyle step for patients who are overweight.
• Continuous positive airway pressure (CPAP) is the most effective medical treatment. CPAP uses a device that delivers slightly pressurized air to keep the airways in the throat open during the night. [See CPAP section in this report.]
• Dental devices are an alternative treatment for patients who cannot tolerate CPAP. They are not as effective as CPAP but are an option. For dental devices, the American College of Physicians recommends the mandibular advancement device (MAD). [See Dental Devices section in this report.]

Other Treatments

Medications

The American College of Physicians does not find evidence to support the use of medications for treatment of OSA. In general, drugs are not very helpful except for specific situations. Medications that treat accompanying disorders associated with sleep apnea may be helpful. For example, thyroid hormone may help improve sleep apnea in patients who have an underactive thyroid gland (hypothyroidism). Intranasal corticosteroids may be helpful in some cases for children with sleep apnea.

Modafinil (Provigil), which is also used to treat narcolepsy, is the only drug approved by the FDA to treat the sleepiness associated with obstructive sleep apnea in patients for whom CPAP does not completely eliminate excessive daytime sleepiness. However, modafinil is meant to be used in combination with -- not as a substitute for -- CPAP. Sleep doctors stress that patients who take modafinil should adhere to CPAP treatment as the drug treats only the symptom of sleepiness, not the underlying cause of obstructive sleep apnea or its complications.

Patients with sleep apnea should be aware that sedatives, narcotics, and anti-anxiety drugs can actually worsen the breathing disturbances that occur with this condition. These medications may cause the soft tissues in the throat to sag and diminish the body's ability to inhale. Patients with sleep apnea should never use sleeping pills or tranquilizers. If undergoing surgery, be sure to inform your surgeon, anesthesiologist, and other doctors of your condition so that they can determine which sedatives, anesthetics, or pain medications are safe and appropriate.

Surgery

Surgery should never be used as an initial treatment for OSA in adults. Surgical treatments for sleep apnea have a number of risks, and there is limited evidence as to their benefit. However, surgery may be an appropriate option for select patients who cannot tolerate or comply with CPAP therapy. [For more information, see Surgery section in this report.]

Continuous Positive Airway Pressure (CPAP)

The best first-line treatment for OSA is a system known as continuous positive airway pressure (CPAP). It is safe and effective for people of all ages, including children.

Patients with OSA who use CPAP feel better rested, have less daytime sleepiness, and have improved concentration and memory. In addition, CPAP may potentially reduce the risks for heart problems such as high blood pressure. For maximum benefit, CPAP should be used for at least 6 to 7 hours each night.

CPAP works in the following way:

• The device itself is a machine weighing about 3 pounds (1.35 kilograms) that fits on a bedside table.
• A mask containing a tube connects to the device and fits over the mouth and nose or just over the nose.
• The machine supplies a steady stream of air through a tube and applies sufficient air pressure to prevent these tissues from collapsing during sleep.

The standard CPAP machine delivers a fixed, constant flow of air. Variations on CPAP include:

• Autotitrating positive airway pressure (APAP). APAP devices automatically respond to changes in the sleeper's breathing patterns by adjusting and varying the air pressure flow throughout the night. Some patients find this makes CPAP easier to tolerate.
• Bilevel positive airway pressure (BiPAP). BiPAP systems deliver two different pressures, a higher one for inhalation (breathing in) and a lower one for exhalation (breathing out). It might also initiate breaths for patients with central sleep apnea.

Side Effects and Getting Used to the Device

CPAP works well, but it can take some time to get used to, especially for the first few nights. Here are some tips to help you adjust:

• Masks are available in many different styles ranging from full face masks (covering the whole face in addition to mouth and nose) with adjustable straps to half masks with nasal pillows. Masks also come in different sizes. When choosing a mask, try on different styles and sizes to see which feels most comfortable.
• Make sure your doctor or CPAP service provider shows you how to adjust the mask for the best fit. A poor-fitting mask can cause skin irritation or sores. Let your doctor know if you develop any skin problems.
• When beginning CPAP treatment, it may help to wear your mask for short periods while you are awake so you get used to how it feels. For the first few nights of treatment, begin with low air pressure and then use the ramp setting to gradually increase the pressure.
• Patients on CPAP often complain of nasal congestion and dry mouth. Many CPAP machines now come with a heated humidifier attachment. Chin straps (to keep the mouth closed) and nasal saline sprays can also help with these problems.
• To help ensure a good night of sleep, follow sleep hygiene practices such as avoiding alcohol and caffeine before bedtime.
• Be sure to clean and maintain your equipment and mask on a daily basis. Your doctor may need to periodically readjust the air pressure settings.

Oral appliances, also called dental appliances or devices, may be an option for patients who cannot tolerate CPAP. The American Academy of Sleep Medicine recommends dental devices for patients with mild-to-moderate obstructive sleep apnea who are not appropriate candidates for CPAP or who have not been helped by it. Although these devices may provide some improvement in patients with moderate-to-severe sleep apnea, CPAP therapy is still needed.

Several different dental devices are available. A trained dental professional such as a dentist or orthodontist should fit these devices. Devices include:

• Mandibular advancement device (MAD). This is the most widely used and most recommended dental device for sleep apnea. It is similar in appearance to a sports mouth guard. MAD forces the lower jaw forward and down slightly, which keeps the airway open.
• Tongue retraining device (TRD). This is a splint that holds the tongue in place to keep the airway as open as possible.

Patients fitted with one of these devices should have a check-up early on to see if it is working; short-term success usually predicts long-term benefits. It may need to be adjusted or replaced periodically.

Benefits of Dental Devices

Dental devices seem to offer the following benefits:

• Significant reduction in apneas for those with mild-to-moderate apnea, particularly if patients sleep either on their backs or stomachs. They do not work as well if patients lie on their side. The devices may also improve airflow for some patients with severe apnea.
• Improvement in sleep in many patients.
• Improvement and reduction in the frequency of snoring and loudness of snoring in most (but not all) patients.
• Few or no complications.

Disadvantages of Dental Devices

Dental devices are not as effective as CPAP therapy. They are often expensive, and since they are custom-made they cannot be returned. Side effects associated with dental devices include:

• Nighttime pain, dry lips, tooth discomfort, and excessive salivation. In general, these side effects are mild, although over the long term they cause nearly half of patients to stop using dental devices. Devices made of softer materials may produce fewer side effects.
• Permanent changes in the position of the teeth or jaw can sometimes occur with long-term use. Patients should have regular visits with a health professional to check the devices and make adjustments.
• In a small number of patients, the treatment may worsen apnea.

Orthodontic Treatments

An orthodontic treatment called rapid maxillary expansion, in which a screw device is temporarily applied to the upper teeth and tightened regularly, may help patients with sleep apnea and a narrow upper jaw. This nonsurgical procedure helps to reduce nasal pressure and improve breathing.

Surgery is sometimes recommended, usually by ear, nose, and throat specialists (otolaryngologists), for severe OSA in adults. A patient should be sure to seek a second opinion from a specialist in sleep disorders. Few randomized clinical trials, the gold standard of medical research, have been conducted to verify the long-term efficacy of sleep apnea surgery.

Uvulopalatopharyngoplasty (UPPP)

The Procedure

Surgery known as uvulopalatopharyngoplasty (UPPP) removes soft tissue on the back of the throat. Such tissue includes all or part of the uvula (the soft flap of tissue that hangs down at the back of the mouth) and parts of the soft palate and the throat tissue behind it. If tonsils and adenoids are present, they are removed. The surgery typically requires a stay in the hospital.

The Goal of Surgery

The goals of UPPP are to:

• Increase the width of the airway at the throat's opening
• Block some of the muscle action in order to improve the ability of the airway to remain open
• Improve the movement and closure of the soft palate

Success Rates

The American Academy of Sleep Medicine (AASM) does not endorse UPPP as a sole procedure for treating OSA. The AASM recommends that patients considering this surgery first try CPAP or dental devices.

There is limited evidence as to the effectiveness of UPPP. Studies suggest that success rates for sleep apnea surgery are rarely higher than 65% and often deteriorate with time, averaging about 50% or less over the long term. Other studies indicate that UPPP may lower the risk of dementia in patients with OSA.

Few studies have been conducted on which patients make the best candidates. Some studies suggest that surgery is best suited for patients with abnormalities in the soft palate. Results are poor if the problems involve other areas or the full palate. In such cases, CPAP is superior and should always be tried first. Many or most patients with moderate or severe sleep apnea will likely still require CPAP treatment after surgery.

Complications

UPPP is among the most painful treatments for sleep apnea, and recovery takes several weeks. The procedure also has a number of potentially serious complications including:

• Infection.
• Impaired function in the soft palate and muscles of the throat (called velopharyngeal insufficiency), which can make it difficult to keep liquids out of the airway.
• Mucus in the throat.
• Changes in voice frequency.
• Swallowing problems.
• Regurgitation of fluids through the nose or mouth.
• Impaired sense of smell.
• Failure and recurrence of apnea. In such cases, CPAP is often less effective afterward.

In general, only a small percentage of patients experience serious complications. Many of these complications can be avoided with proper technique and an experienced surgeon. A patient's health status, including presence of obesity and other health conditions, may also affect outcomes.

Laser-Assisted Uvulopalatoplasty (LAUP)

A variation on UPPP called laser-assisted uvulopalatoplasty (LAUP) is being increasingly performed to reduce snoring. It removes less tissue at the back of the throat than UPPP and can be done in a doctor's office. At this time, however, long-term success rates in the treatment of obstructive sleep apnea with LAUP are very modest, particularly for reducing apneas. Some doctors, in fact, are concerned that if LAUP eliminates snoring, they may miss a diagnosis of apnea in patients who have the more serious condition.

More than half of patients complain of throat dryness after surgery. Throat narrowing and scarring have also been reported. In a minority of patients, snoring becomes worse afterward.

According to guidelines from the American Academy of Sleep Medicine (AASM), LAUP is not routinely recommended as treatment for OSA. According to the AASM, this surgery generally does not help improve symptoms and may actually worsen the condition.

Pillar Palatal Implant

The pillar palatal implant is a noninvasive surgical treatment for mild-to-moderate sleep apnea and snoring. However, the main focus of the procedure is a reduction in snoring. The implant helps reduce the vibration and movement of the soft palate. In this procedure, a doctor inserts 3 short pieces of polyester string into the soft palate.

The procedure can be performed in a doctor's office and takes about 10 minutes. Unlike uvulopalatopharyngoplasty (UPPP), the pillar procedure requires only local anesthesia and has less pain and quicker recovery time. There is still not enough evidence to determine whether it is an effective treatment for OSA.

Upper Airway Stimulator

Approved in 2014, the Inspire Upper Airway Stimulator is a nerve stimulation device that is surgically implanted in a patient's chest. The device senses the patient's breathing patterns and stimulates the hypoglossal nerve, which controls tongue movement, to help keep the airways open. The patient turns the device on and off, before and after sleep, using a remote control.

The FDA approved this nerve stimulator device for a subset of adult patients with moderate-to-severe OSA who cannot tolerate CPAP therapy. The device is not appropriate for patients who have mixed and central sleep apneas, certain anatomical abnormalities of the soft palate, or certain neurological conditions.

In a small study of patients, the device helped reduce breathing pauses and drops in blood oxygen levels. However, some patients experienced a worsening of their sleep apnea. The long-term risks and benefits of this device are not yet known.

The FDA has also approved a newer version of this device which is safe for patients who need to undergo magnetic resonance imaging (MRI).

Tracheostomy

Tracheostomy used to be the only treatment for sleep apnea. It is quite straightforward:

• The surgeon makes an opening through the neck into the windpipe and inserts a tube.
• It is almost 100% successful, but it requires a quarter-size opening in the throat. This produces a number of medical and psychological problems associated with recovery.
• It completely bypasses the area of the obstruction in the throat.

Today, this operation is performed rarely, usually only if sleep apnea is life threatening.

Other Procedures

Other surgical procedures may be appropriate to correct facial abnormalities or obstructions that cause sleep apnea. They may be used alone or combined with each other or with UPPP. Most are invasive and reserved for patients with severe sleep apnea who fail to respond to or comply with CPAP. Overall, there is limited evidence as to their effectiveness in treating OSA. These procedures include:

• Radiofrequency ablation (RFA) for tongue or palate reduction.
• Maxillomandibular advancement (MMA), which moves the upper (maxilla) or lower (mandible) jawbone forward.
• Genioglossus advancement (tongue advancement), in which an opening is cut where the tongue joins the jawbone and the area is pulled forward.
• Genioplasty, which is plastic surgery on the chin.
• Hyoid advancement surgery, in which the movable bone underneath the chin is moved forward, pulling the tongue muscle along with it.

Surgery for Nasal Obstructions

Findings such as a deviated septum can contribute to snoring and other symptoms. Surgical treatment of patients with this finding may improve snoring and sleepiness. However, it does not seem to reduce the numbers of apnea or hypopnea episodes. For patients using CPAP, nasal surgery may improve compliance with using the machine and thereby improve sleep apnea.

Removing Adenoids and Tonsils in Children

Adenotonsillectomy, or surgical removal of the tonsils and adenoids, is a first-line treatment for most children and adolescents with sleep apnea proven by sleep studies. Surgery appears to improve quality of life, symptoms of sleep apnea, and behavior. Sleep studies done after surgery show improvement in the measures of sleep apnea.

This surgery does not appear to improve a child's attention span or school performance. Also, OSA may improve with watchful waiting in up to one half of students.

Complications include respiratory illness, which occurs in about 25% of children after the surgery. The highest risk for respiratory complications is associated with:

• Age under 3 years
• Severe sleep apnea
• Heart complications
• Failure to thrive
• Obesity
• Prematurity
• Recent lung infections
• Certain facial structures
• Neuromuscular disease

The procedure may fail to improve apnea in some patients, such as those with very severe disease. Such children are candidates for continuous positive airway pressure (CPAP) therapy.

Removal of the tonsils and adenoids alone is not an effective treatment for adults with sleep apnea, although the procedure may be effective when combined with UPPP surgery.

• American Sleep Apnea Association -- www.sleepapnea.org
• American Academy of Sleep Medicine -- aasm.org
• National Sleep Foundation -- www.thensf.org/
• National Center on Sleep Disorders Research -- www.nhlbi.nih.gov/about/scientific-divisions/national-center-sleep-disorders-research
• Your Sleep from the American Academy of Sleep Medicine -- sleepeducation.org